Future Science at JLab

12 GeV Updates

25 March 2015

On the Accelerator Tunnel air conditioning contract, Warwick Plumbing & Heating is preparing the concrete slabs for the chillers at grade level near each of the arcs. The chillers are scheduled for delivery in May. To coordinate with accelerator operations and the chiller delivery schedule, minor site preparation was planned for the months of March and April.

18 March 2015

The second superconducting magnet for the new Hall C Super High Momentum Spectrometer (SHMS) was delivered on March 6. The HB (Horizontal-Bend) magnet is the end product of a program that started in 2006 as an R&D collaboration between Jefferson Lab and Michigan State University. Construction began in 2010 and has involved staff of the National Superconducting Cyclotron Laboratory and the Facility for Rare Isotope Beams, as well as MSU. The HB Magnet must be compact but provide a high magnetic field, so that particles scattered at very small angles from the electron beam may be captured and analyzed by the SHMS. It uses saddle-shaped coils wound using reshaped SSC superconducting cable. The coils are tightly enclosed within a thick, heavily-welded stainless-steel H-shaped box. It must resist the 180-ton force that the coils will exert on it when they are fully energized. The HB Magnet is currently passing a series of incoming inspections on the floor of Hall C. It will be put in place on the SHMS carriage in the coming weeks.

At the request of DOE's Office of Nuclear Physics, Stephen Meador, Director of the Office of Project Assessment in DOE's Office of Science, convened a team of seven experts and five observers in an Independent Project Review of the 12 GeV CEBAF Upgrade Project held at Jefferson Lab on March 12. This review was to follow up on remaining questions from the November 2014 review. In the closeout, the committee found that the team had appropriately addressed recommendations from previous reviews. Further, while the superconducting magnets present challenges - with continued emphasis on process control, QA and vendor oversight - the project is positioned to be completed within the established cost and schedule performance baseline.

25 February 2015

The first 12 GeV Hall C magnet, Q1, which arrived in January, has been installed on the Super High Momentum Spectrometer (SHMS) carriage and connected to its cryogenic, power, and control systems. Following a checkout of those services, this superconducting magnet is now being cooled-down in preparation for its final acceptance tests. Close on its heels is the Horizontal Bend (HB) magnet, which is in its final week of construction at Michigan State University. The remaining three SHMS magnets are making steady progress, with the two coils for the dipole having been bonded together, and the final two (of eight) Q2 and Q3 coils now on the winding machines. On the SHMS, the calorimeters have been installed, and now the stands and frames for the remaining detectors have been trial-fitted in the shield house to assure that detector installations may proceed smoothly. Cables for the detectors are being installed now, as are the floor scales that provide experimenters with a precise measurement of the spectrometer angle.

18 February 2015

The 66 modules needed for all four regions of the Silicon Vertex Tracker (SVT) for CLAS12 have been completed and tested at Fermilab and were then transferred to Jefferson Lab. The cooling plate and support structure to mount the first three of the four regions of the SVT are nearing completion, after which assembly will start in the large clean room in the Experimental Equipment Lab. The magnetic shielding materials for the Central Time-of-Flight (CTOF) have arrived and are being checked. The CTOF slats are glued together and are in the process of having the outer light-tight wrapping added, after which photomultiplier tube mounting and testing will start. The large mirror for the High Threshold Cerenkov Counter (HTCC) has been assembled and is being checked. The large containment vessel for the HTCC has been assembled and stood up on edge in preparation for a test mounting of the mirror on its support ring. The work to refurbish the boxes for the Low Threshold Cerenkov Counter, after its long service in CLAS, is nearing completion, and the mounting of components inside the first box has started in the clean tent. Calibration work for the detectors already mounted on the Forward Carriage (Forward Time-of-Flight, Preshower Calorimeter, and Electromagnetic Calorimeter) has proceeded steadily, and the calibration plans for the entire CLAS12 were recently reviewed.

11 February 2015

The accelerator tunnel air conditioning contract vendor, Warwick Plumbing & Heating, made excellent progress during the January scheduled accelerator down (SAD) period. All of the 132 chilled beams are installed, and the majority of the chilled water and fire protection piping is also installed. The remaining piping work in the accelerator tunnel will be completed during the Summer 2015 SAD. Also during the January SAD, Warwick connected and commissioned the backup cooling towers for the North and South Access low-conductivity water systems. These towers, along with the previously installed 12 GeV cooling towers at maximum capacity, support accelerator operations during the demolition of the old cooling towers under the Utilities Infrastructure Modernization (UIM) project.

28 January 2015

The Physic Division held an equipment readiness review of the Super High Momentum Spectrometer Q1 magnet on Jan. 21. No major issues were identified and cooldown of the Q1 magnet will soon commence. The final 12 GeV Upgrade civil construction activity (tunnel air conditioning) is well underway. The related work in the tunnel involved drilling into the overhead to install hangers for the chill beams and associated piping. The subcontractor used a drilling tool for the overhead work. This apparatus allowed the subcontractor to apply an engineered solution to eliminate the ergonomic stresses to the workers, and the attached HEPA vacuum provided local capture ventilation for silica generated during the drilling. During the monthly progress meeting, the feedback from the subcontractor was that the tooling provided the added benefit of significantly increased efficiency for the task.

21 January 2015

The first of seven superconducting spectrometer magnets being built as part of the 12 GeV CEBAF Upgrade project has been delivered to Jefferson Lab. The first quadrupole magnet (Q1) for the Super High Momentum Spectrometer in Hall C is a clone of the High Momentum Spectrometer Q1 magnet; a cold iron design with a 40 cm warm bore, 11 GeV/c performance and a gradient of 7.9 T/m. It was built by Scientific Magnetics, Inc., in the UK and arrived on site on Jan. 13. Acceptance tests are underway. The Physics Division is convening an equipment readiness review for the new Q1 on Jan. 21 to assess the readiness for full, safe operation.